Ordinarily, governments attempt to promote competition in markets. Why do governments use patents to block entry into some markets when this prohibits competition?
A. Patents are justified because they are an important means for creating network externalities.
B. Patents encourage firms to spend money on research necessary to create new products.
C. Politicians sometimes succumb to pressure from lobbyists to grant favors to businesses for political reasons.
D. Patents are an important source of government revenue.
